Time delay triggering unit

ABSTRACT

A triggering unit is provided which will release at a preset time a device it is carrying such as a braking parachute. The triggering unit is housed in a missile capable of being fired through a gas or liquid medium and comprises a primary release mechanism which is connected to a slidable rod. The rod is arranged in the missile housing so that it must move against a force set up by the medium through which the missile passes or the friction forces between the rod and the housing. The rod, which is triggered by the primary release mechanism, will move a specified distance necessary to release the device carried by the unit. The time required for the shaft to move the specified distance is controlled by the forces against which the shaft must move.

United States Patent {72] Inventor John M. Alban 3,014,308 12/1961Parris 46/86 (C) 173 West 188th St.. Bronx. 10468 3.452.466 7/1969Heartness .4 43/6 1968 Primary Examiner-Ant0n O. Oechsle 1 Pmemed 197Assistant Examiner-Paul E. Shapiro Attorney-Eyre, Mann & Lucas [54] TIMEDELAY TRIGGERING UNIT 2 claims 7 Drawmg ABSTRACT: A triggering unit isprovided which will release [52] U.S.Cl 273/1065, at a preset time adevice it is carrying such as a braking 8 parachute. The triggering unitis housed in a missile capable of [51] Int. Cl F4") 5/02 being firedthrough a gas or liquid medium and comprises a 1 1 Field of Search273/1065; primary release mechanism which is connected to a slidable43/6146/86 rod. The rod is arranged in the missile housing so that itmust move a ainst a force set u b the medium throu h which the [56}References cued missile iasses or the fricti zm i'orces between the rodand the UNlTED STATES PATENTS housing. The rod, which is triggered bythe primary release 1,079,200 1 1/1913 Wilde 46/86 mechanism, will movea specified distance necessary to 1,713,432 5/1929 Griggs 46/86 (A)release the device carried by the unit. The time required for 2,607,1598/1952 Hunt et a1. 46/86 the shaft to move the specified distance iscontrolled by the 2,748,529 6/1956 Swan 46/86 (C) forces against whichthe shaft must move.

PATENTED JUH22 19?:

SHEET 1 OF 2 PATENTEH JUN22 Ian SHEET 2 OF 2 QNN INVENIOR. HN M. ALBANATTORNEYS his TIME DELAY TRIGGERING UNIT The present invention relatesto an improved self-contained triggering unit which is inexpensive tomanufacture, has few moving parts, is small enough to be carried in thehousing of a missile and requires no remote parts for operation. Theunit can release at a preset time a device such as a braking parachuteto slow and stop the missile s flight, or other devices such as dyemarkers for indicating the location of the missile. Because thetriggering unit is so compact and requires no remote parts foroperation, it has particular utility in arrow shafts and watergun spearsfor stopping the shaft or spear after it has travelled a specifieddistance. The triggering unit also is useful in toy rockets and planes.

The triggering unit in accordance with the invention comprises a primaryrelease mechanism carried by a missile and which acts upon a slidablerod. The rod, in turn, is slidably mounted in a housing. Preferably, thehousing which carries the rod is the missile housing in order to reducethe overall weight of the entire unit. This is particularly importantwhere the triggering unit is to be assembled in an arrow or spear inwhich case the effect of drag on the arrow or spear because of excessiveweight should be avoided. The primary release mechanism, which acts uponthe rod, is arranged so that once the missile is fired it will permitthe rod to slide within the housing. The rate at which the rod moves iscontrolled by resulting the forces against which the rod must move.These forces are set up by the medium through which the missile passesor the forces caused by the friction between the rod and the housing.

A device such as a braking parachute, which is carried by the missile,and controlled by the rod will be released after the rod has moved aspecified distance within the housing. Once the parachute has beenreleased it will slow and then abort the flight of the missile. Thedistance that the missile travels before being slowed and stopped iscontrolled by regulating the speed at which the rod moves within thehousing. More particularly, the average velocity of the missilemultiplied by the time it takes the rod to move from its preset positionto its triggering position equals the total distance the missile willtravel before the parachute will act to abort the flight. Because theentire triggering unit is carried within the missile, there are none ofthe problems or complexities of using ground control means to triggerthe unit. Up until this invention, the only devices which could be usedin arrows or spears for slowing the device required the use of groundcords or devices which could only stop the arrow after it contactedfoliage along the ground. The triggering unit of the present inventioneliminates these drawbacks by having the missile carry the entiretriggering unit which can release the parachute in midflight.

The importance of the present invention when used in an arrow orunderwater spear becomes evident when it is realized that loss of mostarrows in hunting or target shooting results from missing the target andfalling into the surrounding foliage. With the present triggering unit,the braking device can be released after the arrow should have contactedthe target. lf the target is missed the braking means will be released,stopping the flight of the arrow just beyond the target for easyrecovery.

Another advantage of the triggering unit is that because there are veryfew moving parts, there is very little chance that the unit will fail tofunction. In addition, since the parts of the unit are arranged at theback portion of the housing and most of the impact forces are absorbedat the front end upon contact on the target, there is very little chanceof damage to the rearwardly mounted working parts of the unit.

Another important feature of the triggering unit is that it can bereadily reassembled in the field after it has been used without the needfor any special equipment or personnel. The reassembly procedure onlyrequires reinserting the rod into the missile housing and resetting theprimary release mechanism.

Further details of the present invention and its advantages will bereadily understood by reference to the accompanying drawings whichillustrate preferred embodiments of the invention and in which:

FIG. 1A and 1B are a cross-sectional view of the missile with theprimary release mechanism in the unset position;

FIG. 2 is a cross-sectional view of the back portion of the missile withthe primary release mechanism in the set position;

FIG. 3 is a section taken along the line 3-3 of FIG. 2;

FIG. 4 is a modified form of the primary release mechanism;

FIG. 5 shows a missile carrying the primary release mechanism of FlG. 4with the primary release mechanism in the set position; and

FIG. 6 shows the missile of FIG. 5 after the primary release mechanismhas been triggered.

Referring to FIG. 1A and 1B, for purposes of illustration the missile isshown as an arrow 10 having a shaft or stele 12, a pointed head 14secured to theforward end of the shaft and a nock 16 secured to the backof the shaft. Fletching or feathering not shown in the drawing isusually provided near the end of the shaft 12 to stabilize the flight ofthe arrow 10.

The shaft 12 is a hollow tube made of a suitable structural materialsuch as wood or metal. An opening 13 is provided in the forward end ofthe shaft, the importance of which will be explained herein.

Slidably seated in the shaft 12 is a primary release mechanism 18, slidemeans 19 having the general shape of a cylindrical rod and hereinafterreferred to as a rod, and a valve block 20. The primary releasemechanism 18 comprises a housing 21, a stem 22, a locking cam follower23, a pin 24 and a spring 26. The housing 21 as can be seen from FlGS.1A and 2 has cam surfaces 28 along its inside wall. The cam surfaces inwhich there are at least two, are spaced around the periphery of thehousing 21 and have two extended portions 28a connected by a ledge 28b.The importance of the cam surfaces will be explained below.

The stem has a narrow portion 30 which passes through an opening 31 inthe nock 16. The narrow portion has a slot 32 cut therein as can be seenin FIG. 1A. The stem also has a wider portion 34 which is hollowed outto form an opening 35. Around the periphery of the sidewalls of thewider portion 34 are teeth 36 which extend downward to form points 38 atthe bottom of the wide portion. The cam follower 23 is made from a tubehaving a narrowed end 37 and a flanged portion having teeth 40 with camsurfaces 42 molded thereon.

The primary release mechanism 18 is assembled by inserting the camfollower 23 into the opening 35 of the stem so that the teeth 36 of thestem are in contact with the teeth 40 of the cam follower. One end ofthe pin 24 is then inserted into the cam follower 23 so that it rests upagainst the narrowed end 37 of the cam follower 23 and the spring 26 ismounted on the other end of the pin. The spring 26 is held in place by astop 44 located on the pin and the rod 19. The stop 44 can be made in aform of a slidable collar so that the tension in spring 26 can bevaried.

The rod 19 is a unitary structure slidably seated in the shaft 12 havingfour major portions. The first portion 46, against which spring 26rests, and the second portion 50, having a smaller outside diameter thenthe first portion, are provided with a continuous bore 50 therethroughas can be seen from FIGS. 1A and 3. The bore 50 is made large enough toreceive the pin 24. The housing 21 of the primary release mechanism 18is attached to the first portion 46 of the rod 19 by screwing theportion onto the housing as illustrated in FIG. 2. However, other meansknown to the art can be used to attach the first portion 46 to thehousing 21. The second portion 48 has a slot 52 passing completelythrough it, as best seen in FIG. 3. Two jaw members 54 having flangedsections 56 are dropped into the slot 52 and held in a closed positionby an elastic band 58 wrapped around the exterior of the jaw members.When the jaw members 54 are in the open position, the flanged section 56is seated in a recess 60 cut into the inner wall of the shaft 12.

The third portion 62 of the slidable rod 19 carries the braking meanswhich for purposes of illustration is shown as a parachute 64. Theparachute 64 is slidably mounted on the third portion 62 by means of aslip ring 66. The parachute is then carefully wrapped around the thirdportion 62 so that it can open when it is exposed to air currents.

The fourth portion 68 of rod 19 has a heavy duty spring 70 permanentlymounted on its forward end as shown in FIG. 1B. The other end of thespring is permanently attached to the valve block 20.

The valve block 20 has an air passage 72 (see H6. 18) in which avalvepin 74 is seated. The valve pin 7:1, which also passes through theopening 13 of the shaft 12, acts to regulate the amount of air which canbe drawn into the valve block 20 and to hold the valve block in placewithin the shaft. An annular member 76 is provided in order to absorbthe inertia of the valve block 20 on impact of arrow 10 against a targetand thereby prevent application of the inertia forces upon pin 74. Thisavoids any risk of shearing or other damage to pin 74. lt should beunderstood however that the annular ring can be eliminated by using ashaft 12 which is solid at its front end. Thus the valve block can restup against the solid portion of the shaft. However, in order tofacilitate manufacture it has been found that a tubular shaft ispreferred with use of an annular ring to hold the valve block in place.

As brought out above, the head 14 of the arrow is fastened to the frontof the shaft 12. The preferred method of at tachment is to providematching threads on the shaft and head and then screwing the head ontothe shaft. However, it should be understood that other methods ofattachment can be used such as using a resin or adhesive between theshaft and the head.

In assembling the triggering unit for firing, the primary releasemechanism 18 and the slidable rod 19 are pushed into the shaft 12 inorder to compress the spring 70. The nock 14 is then mounted on theshaft by means of an interlocking grove 77 and tongue 79 and held inplace by a friction fit at 78. While the unit is held in this position,stem 22 is pushed forward which causes the spring 26 to compress and tomove the pin 24 through the bore 50. As the pin 24 moves forward, itwill spread the jaws 54 apart and seat the flanges 56 thereof within therecess 60 of the shaft 12. The seated jaws will support and maintain thespring 70 in its compressed state. When the stem 22 is pushed forward,the cam follower 23 will move forward beyond the cam surfaces 28. Thestem 22 is then released causing the cam surfaces 42 of the cam follower23 to engage the extended portions 280 of the cam surfaces 28. When thisoccurs, the cam follower 23 will rotate a small angular increment toseat the cam surfaces 42 on the ledge 28b and lock the cam follower inthe forward position shown in FIG. 2. The cam follower 23, which is nowlocked in the forward position, will hold spring 26 in its compressedstate and hold pin 24 between the jaws 541.

In firing the arrow 10, a bow string (not shown) is placed in the nock16. When the arrow 10 is drawn, the bow string will move the stem 22forward to engage the points 38 of the teeth 36 with the points of theteeth 40 and unseat the cam follower from the ledge 28b. When the arrow10 is released from the bow, the spring 26 will act against the camfollower 23 causing the teeth 40 to slide off the points 38 of teeth 36and rotate the cam follower 23 a small angular increment so that the camsurfaces 42 of the cam follower will not engage the cam surfaces 28 ofthe housing, allowing the cam follower to return to its originalposition shown in FIG. 1A. The spring 26 will also move the pin 24rearwardly out of bore 50 of the second portion 49 of the rod 19. Theelastic band 56 will cause the jaws 54 to close unseating the flanges 56from the recess 60 in the shaft 12. When the arrow 10 is released fromthe bow, the spring 70 which is no longer restrained will start to movethe rod 19 towards the back of the arrow 10. The rate at which the rod19 can move is directly related to the amount of air allowed throughport 72 of the valve block 20. Thus, if the valve 74 is closed so no aircan pass through the port, the potential energy stored in the spring 70will be insufficient to break the vacuum formed in the shaft 12 and thusthe rod 19 cannot move. If, however, the valve 74 is completely opened,the spring 70 can expand at its normal rate since no vacuum will beformed in the shaft 12 as a result of air entering the shaft by way ofthe port 72. It can now be seen that the rate of movement of the rod 19will depend on the degree the valve 74 is opened and the strength of thespring 70. The friction forces between the housing 21 and the rod 19 andthe inside walls of the shaft 12 can be reduced to inconsequential bycoating the inside walls of the shaft with a suitable material such asTeflon or a lightweight grease or oil. However, if the device is used ina toy where a critical release time is not necessary, the need for avalve can be eliminated by not making the shaft airtight and relying onthe friction forces between the inside walls of the shaft 12 and thehousing 21 and the rod 19 to slow the movement of the rod and housingout of the shaft 12.

As brought out above, after the arrow has been tired from the bow, thespring 70 will move the rod 19 and in turn the housing 21 out the backof the shaft. The nock 16, which is frictionally held to the shaft 12 at78, will disengage from the shaft but will remain attached to the narrowportion 30 of the stem 22 by means of a spring-loaded setscrew 80 whichis seated in the nock and the slot 32. After the nock 16 is unseatedfrom the shaft 12, the primary release mechanism 18 and the rod 19 willmove out of the shaft. When the third portion 62 of the rod 19 moves outof the shaft 12, the air currents will open the parachute 64 and shortthe flight of the arrow 10. The triggering unit will not be lost whenthe flight is interrupted since the spring 70 is permanently attached tothe arrow shaft 12 by means of the valve block 20 and the rod 19 whichin turn is attached to the primary release means 18. Of course, if thetarget area is hit, the rod 19 does not have opportunity to leave theshaft 12 and therefore the flight is not stopped.

The triggering unit is readily reassembled by reinserting the primaryrelease means 18 and the rod 19 into the shaft 12 which will compressthe spring 70. The stem 22 is then moved forward and released which willcause the cam follower 23 to rotate and seat the cam surfaces 42 on theledge 28b in the manner described above. The pin 24, which will alsomove forward and be held in the forward position as a result of the camsurfaces 42 being seated on the ledge 2811, will compress spring 26 andopen jaws 5 1 to seat the flanges 56 of the jaws in the recess of theshaft 12 to hold the spring 70 in its compressed position as shown inFlG. 2. The triggering unit has now been set and the arrow 12 is againready for use.

Another embodiment of applicants invention is shown in H08. 4 through 6.The missile in these figures, for purposes of illustration, is a spear90 for use underwater with a conventional spear gun (not shown).Referring to FIG. 5, the spear 90 consists of a shaft 92 having ahollowed front portion and made from a suitable material such as steel.The wall of the shaft 92 is provided with a small opening 94 (HO. 5) andtwo slots 96, the lengths of which are parallel to the long axis of the1 shaft. A head 98 is secured to the forward end of the shaft 92.

The head 92 has a neck region 100 which extends over a small portion ofthe shaft 92 beyond the point of attachment of the head to the shaft.When the head 98 is secured to the shaft 92, the neck region 100 doesnot contact the shaft but leaves an annular space 102 between the shaftand neck region.

Members 104, constituting a primary release mechanism, have the generalshape of dished semicircles and are mounted on a pair of cylindricalmembers 106. The cylindrical members 106, which act as braking means forthe spear, have curved cutaway portions 107 terminating in tapered ends108. The tapered ends 108 have openings 110 for mounting purposes aswill be explained hereinafter. The cylindrical members 106 are mountedon rod-shaped slide means 112, having an opening therein for receiving apivot pin ll 14.

In assembling the device, the slide means 112 is seated in the shaft 92and the opening for receiving the pivot pin 114 is aligned with theslots 96. The cylindrical members 106 are then placed over the shaft 92so that the openings 110 are also aligned over the opening in the slidemeans 112. The pivot pin 114 is then inserted through the other openings110, the opening in the slide means 112 and out through the otheropenings 110 and locked in place by wedging or equivalent means. Thehead 98 is then screwed to the shaft 92 by means of matching threads 115and 116 in the head and shaft respectively (FIG. 5). lt should beunderstood that other means of attaching the head to the shaft can beused such as the use of resins, adhesives or rivets. The cylindricalmembers 106 are then moved forward toward the front end of the spearinto the annular space 102. The triggering unit is now set and the spearis ready for firing.

The primary release mechanism 107 operates when the spear 92 is firedfrom a conventional spear gun (not shown). Prior to firing, water entersthe inner spaces and hollow interior of shaft 92 filling these up. Asthe spear proceeds through the water, after it is fired, the pressure ofwater against the primary release means 104 causes the slide means 112to slide backwardly away from the front end of the spear. The rod 112pushes against the water contained in the hollow shaft space to the rearof slide means 112 and this reverse pressure is relieved by passage ofthe water out through opening 94. Therefore, the rate at which the slidemeans 112 moves will depend on the size of the openings 94. If desired,a valve can be provided in the opening 94 to change the size of theopening and thus the rate of speed of the slide means 112. As the slidemeans 112 continues to move, the portion of the cylindrical members 106seated in the annular space 102 will withdraw from this space causingthe cylindrical members to separate from each other by'a pivoting motionabout the pivot pin 114 (FIG. 6). The curved cutaway portions 107 of thecylindrical members 106 are shaped to allow the cylindrical members toopen a fully extended position shown in FIG. 6 without any interference.

Prior to withdrawal of the cylindrical members 106 from the annularspace 102, the spear travels with very little interference since theprimary release mechanism 104 offers only sufficient land surface toslide the slide means 112 but not to materially effect the speed of thespear. When the cylindrical members 106 open, the travel of the spear isaborted because of the large land surfaces of the cylindrical memberswhich offer a large resistance to the water. The period of unimpededtravel of the spear, before cylindrical members 106 open, is preferablyselected as the maximum approximate range to a target that is expectedto be encountered, whereby the aborting of the spear travel will notoccur prematurely. As previously explained, this time is controlledprimarily by the size of the opening 94. If the spear travel is aborted,the triggering unit is reset by pivoting the cylindrical members 106down on top of the shaft 92 and inserting the forward ends of thecylindrical members into the annular space 102.

In the embodiment of the invention illustrated in FIGS. l 3, markermaterial such as dyes or smoke-producing chemicals may be packaged in arupturable bag and placed adjacent the parachute 64, so that the markermaterial may be ejected simultaneously with the parachute to aid inlocating the aborted missile. I

It will be understood that it is intended to cover all changes andmodifications of the preferred embodiments of the invention hereinchosen for the purpose of illustration which do not constitutedepartures from the spirit and scope of the invention.

lclaim:

1. A triggering unit mounted in association with an elongated missilefor slowing the travel of the missile when fired through a fluid mediumwhich comprises:

a. a member mounted to slide along the length of said missile from afirst to a second position,

b. braking means carried by said missile and controlled by said member,said braking means being disabled when said member is in said firstposition and being actuated into braking operation when said rnembenisin said second position, means for maintaining said braking meanspositioned between opposite ends of said missile in both the disabledand actuated conditions, said braking means when in actuated conditionextending out from the exterior of the body of said missile andtransverse to the long axis of the missile to slow missile travel,

c. means for urging said member from said first position to said secondposition,

d. and means for controlling the sliding movement of said member fromsaid first position to said second position to occur over apredetermined time interval, whereby said braking means is actuated at apredetermined time after said missile is fired,

e. wherein said member includes a rod having four portions, the firstportion being attached to a primary release means, the second portioncarrying a pair of jaws having flanges thereon for engaging a slot inthe missile housing, the third portion carrying the braking means andthe fourth portion being attached to a spring which assists the slidingmovement of the member, said flanges of said jaws when engaged in theslot of the missile housing will hold said spring in a compressed state.

2. The triggering unit of claim 1 wherein an elastic band is placedaround the jaws to hold the jaws in a closed position.

1. A triggering unit mounted in association with an elongated missilefor slowing the travel of the missile when fired through a fluid mediumwhich comprises: a. a member mounted to slide along the length of saidmissile from a first to a second position, b. braking means carried bysaid missile and controlled by said member, said braking means beingdisabled when said member is in said first position and being actuatedinto braking operation when said member is in said second position,means for maintaining said braking means positioned between oppositeends of said missile in both the disabled and actuated conditions, saidbraking means when in actuated condition extending out from the exteriorof the body of said missile and transverse to the long axis of themissile to slow missile travel, c. means for urging said member fromsaid first position to said second position, d. and means forcontrolling the sliding movement of said member from said first positionto said second position to occur over a predetermined time interval,whereby said braking means is actuated at a predetermined time aftersaid missile is fired, e. wherein said member includes a rod having fourportions, the first portion being attached to a primary release means,the second portion carrying a pair of jaws having flanges thereon forengaging a slot in the missile housing, the third portion carrying thebraking means and the fourth portion being attached to a spring whichassists the sliding movement of the member, said flanges of said jawswhen engaged in the slot of the missile housing will hold said spring ina compressed state.
 2. The triggering unit of claim 1 wherein an elasticband is placed around the jaws to hold the jaws in a closed position.